DE2647854C3 - Process for the production of adducts from maleic anhydride with liquid diene polymers - Google Patents

Description

(1) an imidazole of the general formula

C-X

(l-a)

R. »

C-X

(1-b)

in which R ₁ , R ₂ and R _{3 represent} hydrogen or halogen atoms or alkyl radicals with 1 to 8 carbon atoms and X represents a hydrogen or halogen atom, an alkyl radical with 1 to 8 carbon atoms, a phenyl or mercapto group, (2) a thiazole of the general formula

(M-a)

R., N

C-X '

in which R ₄ , Rs and R _{6 are} hydrogen or halogen atoms, alkyl radicals having 1 to 8 carbon atoms or phenyl groups and X 'is a hydrogen or halogen atom, an alkyl radical having 1 to 8 carbon atoms, a phenyl, mercapto, hydroxyl or hydroxymethyl group or represent a group of the general formula —SNR7R8, in which R7 and R _{8 represent} hydrogen atoms, alkyl radicals with 1 to 8 carbon atoms or alicyclic radicals or

(3) a metal salt of mercaptothiazoles of the general formula

C-S

(II l-a)

or

C-S

(111-b)

in which R ₉ , Rio and Rn represent hydrogen or halogen atoms, alkyl radicals with 1 to 8 carbon atoms or phenyl groups and M represents a zinc, aluminum, magnesium or calcium atom.

begins.

Natural unsaturated oils, such as Soybean oil Linseed oil or castor oil, reacted with maleic anhydride. There have been numerous attempts undertaken the natural unsaturated ö'.e through to replace other connections. For example, JP-AS 21 193/61 describes the preparation of intermediates for alkyd resins by reacting cyclododecatriene with maleic anhydride and JP-AS 954/71 the production of a modified polymer by adding maleic anhydride to low molecular weight polybutadiene with at least 80% 1,2 structure described. Furthermore, JP-AS 7269/71 describes a process for the preparation of water-soluble Polymers by neutralizing the aforementioned modified polymer or its ester with Ammonia or an amine.

When maleic anhydride is added to polymers of conjugated diolefins, the Adducts generally made by heating. This implementation generally also involves one Crosslinking of the double bond of the polymers with other polymer chains after a radical Mechanism. This leads to an increase in the viscosity of the reaction mass. With increasing Viscosity, the reaction mass forms a gel, which makes post-treatment of the product very difficult. Self if the gel does not form, the increase in viscosity leads to the reaction with maleic anhydride to various difficulties. For example, those made from the products obtained form Paints Paint films with inferior physical properties. Furthermore, the control of the Implementation of the maleic anhydride and the viscosity of the reaction mass to produce the maleic anhydride adducts of suitable viscosity for paints is very difficult.

To overcome these disadvantages, the made various attempts. For example, in JP-AS 3547/73 the use is cyclic Ethers, aldehydes or ketones are described as gelation inhibitors during adduct formation with maleic anhydride. In JP-AS 3544/73 is the use of Amides, in JP-OS 7895/75 the use of catechols, in JP-OS 87 491/75 the use of naphthols and in JP-OS 1 32 013/74 the Use of phenothiazines described.

JP-AS 26 870/68 describes the production of adducts from maleic anhydride and a liquid polybutadiene with at least 50% cis-1,4 structure and a viscosity of 30 to 30,000 cP, in particular 8G> to 10,000 cP 50 ⁰ C described in the presence of copper compounds. The presence of the copper compound increases the viscosity of the reaction mixture :; reduced. JP-AS 44 557/72 describes the use of a complexing agent, such as acetylacetone, in this adduct formation.

The invention is based on the object of providing adducts of maleic anhydride with liquid diene polymers with a content of 2 to 70 percent by weight attached maleic anhydride to create the have the lowest possible gel content. The solution to this problem is based on the surprising Finding that even small amounts of certain imidazoles, thiazoles and metal salts of mercaptothiazoles are particularly effective gelation inhibitors represent the reaction of maleic anhydride with the liquid diene polymers.

The invention thus relates to the method characterized in the claim.

In comparison to the gelling inhibitors known from JP-AS 26 870/68 and 4 * 557/72, the Gelation inhibitors used according to the invention: various advantages. For example, they decrease in smaller amounts the viscosity of the reaction mixture in a sufficient and satisfactory manner. this is advantageous in the production of resins for paints, since small amounts of gelation inhibitor do not interfere with the paints. Furthermore, the Discoloration of the adducts prepared according to the invention by the gelation inhibitors is significantly less than when using the known gelation inhibitors. This affects the quality of the dating Resins made from adducts.

In the inventive method, liquid polybutadiene, polyisoprene, liquid butadiene and Isoprencopolymerisate having a molecular weight of 150 to 5000 and a viscosity of 2 to 50 00OcP at 3O have the liquid diene polymers ⁰ C and with any proportion of cis-, trans-, vinyl - and 3,4 structure can be used. When using low molecular weight copolymers of butadiene or isoprene with styrene, the copolymers should contain a maximum of 40 percent by weight of styrene basic units. The liquid diene polymers can be prepared by customary processes, for example by the process described in US Pat. No. 3,428,699.

For the addition of maleic anhydride to the liquid diene polymer in the presence of the gelation inhibitor, the reactants are in fed into a reaction vessel in any order and then until the adduct is completely formed implemented at elevated temperature. In practice, for example, the liquid diene polymer and the gelation inhibitor initially in a reaction

10

20th

tion vessel and allowed to stand at a temperature of 10 to 270 ⁰ C for up to 20 hours. ^{The maleic anhydride is then entered and the mixture obtained is heated to temperatures of 120 to 230 0} C, preferably 170 to 210 ⁰ C, for 1 to 10 hours in a stream of nitrogen and with stirring reaction vessel initially introduced and 170 are preferably heated to 210 ⁰ C then 1 to 10 hours in a nitrogen stream while stirring at 120 to 230 ° C. Since the adduct formation proceeds almost quantitatively, the recovery of unreacted compounds from the reaction mixture is generally not necessary. The amount of attached maleic anhydride in the product is usually 2 to 70 percent by weight. If the maleic anhydride adduct is mixed with an inorganic pigment to produce a paint, the maleic anhydride content in the adduct is preferably at least 2 percent by weight

According to the invention, at least one of the following compounds is used as a gelation inhibitor:

(1) Imidazole of the general formula

(1-a)

b0

C-X

(I-b)

R., N

in which Ri, R2 and R3 are hydrogen or halogen atoms or alkyl radicals having 1 to 8 carbon atoms and X represents a hydrogen or halogen atom, an alkyl radical having 1 to 8 carbon atoms, a Represents phenyl or mercapto group. Specific examples of these compounds are Imidazole, 4-methylimidazole, 2-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 2,4-dimethylimidazole, 4,5-dimethylimidazole, 2,4-diphenylimidazole, 4,5-diphenylimidazole, 2,4,5-triphenylimidazole, 2-bromo-4-methylimidazole, 2- bromo-4-phenylimidazole, 4-bromo-1-methylimidazole, 2,4-dibromoimidazole, 2,4,5-tribromimidazole, 2,4,5-triiodimidazole, 2-mercaptoimidazole, 2-mercapto-4-methylimidazole, 2-mercapto-4,5-dimethylimidazole, 2-mercapto-4-phenylimidazole, benzimidazole, 2-methylbenzimidazole, 2-ethylbenzimidazole, 2-vinylbenzimidazole, 2-phenylbenzimidazole, 2-benzylbenzimidazole, 5-methylbenzimidazole, 2-mercaptobenzimidazole and 2-mercapto-5-methylbenzimidazole. The mercaptoimidazoles and benzimidazoles are preferred;

(2) Thiazole of the general formula

_χ ·

(Il-a) Of the aforementioned thiazoles, the benzothiazoles are particularly preferred;

(3) Metal salt of mercaptothiazoles of the general Formula Hl-a and IH-b

(Ill-a)

-x-

or

in which R *, R5 and Re are hydrogen or halogen atoms, alkyl radicals with 1 to 8 carbon atoms or phenyl groups and X 'is a hydrogen or halogen atom, an alkyl radical with 1 to carbon atoms, a phenyl, mercapto, hydroxyl or hydroxymethyl group or a Represent group of the general formula -SNR ₇ Re, in which R7 and Rg represent hydrogen atoms, alkyl radicals with 1 to 8 carbon atoms or alicyclic radicals. Specific examples are 2-methylthiazole, 4-methylthiazole, 5-methylthiazole, 2,4-dimethylthiazole, ^ S-Dimethylthiazole. ^ S-Dimethylthiazole,

2,4,5-trimethylthiazole, 2-ethylthiazole, 2-phenylthiazole, 4-phenylthiazole, 5-phenylthiazole, 2-methyl-4-phenylthiazole, 4-methyl-5-phenylthiazole, 4 ^ -diphenylthiazole, 2-methyl-4,5-diphenylthiazole, 2-methylcyclohexenothiazole, 2-mercaptocyclohexenothiazole, 2-chlorothiazole, 2-bromothiazole, 2-chloro-4-methylthiazole, 4-chloromethylthiazole, 4-chloromethyl-2-methylthiazole, 4-chloromethyl-2-phenylthiazole, 2-hydroxy-4-methylthiazole, 2-methoxy-4-methylthiazole, 2-hydroxy-5-methylthiazole, 2-hydroxy-4,5-diphenylthiazole, 2-hydroxymethyl-4-methylthiazole, 2-aminothiazole, 2-amino-4,5-diphenylthiazole, 2-amino-5-phenylthiazole, benzthiazole, 2-ethylbenzthiazole, 2-methylbenzthiazole, 2-phenylbenzothiazole, 2-chlorobenzothiazole, 2-hydroxybenzothiazole, 2-hydroxy-5-methylbenzothiazole.

2-aminobenzothiazole, 2-amino-6-methylbenzthiazole and 2-mercaptobenzothiazole.

If the radical X 'represents a group of the general formula -SNR ₇ Re, the thiazoles are generally referred to as thiazylsulfenamides. Specific examples of these compounds are

N-ethylthiazylsulfenamide, N-propylthiazylsulfenamide, N-butylthiazylsulfenamide, N-amylthiazylsulfenamide, N-octylthiazylsulfenamide, N-cyclohexylthiazylsulfenamide, N-oxydiethylenethiazylsulfenamide, N-Ethylbenzthiazylsulfenamide, N - Propylbenzthiazy lsulfenamid, N-butylbenzthiazylsulfenamide, N-octylbenzthiazylsulfenamide, N-Cyclohexylbenzthiazylsulfenamide and N-Oxydiäthylenbenzthiazylsulfenamid.

(Ill-b)

in which Rg, Rio and Rn are hydrogen or halogen atoms, alkyl radicals with 1 to 8 carbon atoms or phenyl groups and M represents a zinc, aluminum, magnesium or calcium atom. Specific examples are the zinc, calcium, magnesium and aluminum salts of

2-mercaptothiazole, 2-mercapto-4-methylthiazole, 2-mercapto-5-methylthiazole,

2-mercapto-43-dimethylthiazole,

2-mercapto-4-ethylthiazole,

2-mercapto-4-chlorothiazole,

2-mercapto-4-phenylthiazole,

2-mercapto-4-methyl-5-phenylthiazole,

2-mercaptocyclohexenothiazoi and

2-mercaptobenzothiazole.

Of these metal salts, the metal salts of the benzothiazoles are particularly preferred

Of the gelation inhibitors described above, the thiazoles and the metal salts are Mercaptothiazoles particularly preferred Der Gelie inhibitor is used in an amount of 0.001 to 5 Percent by weight, preferably 0.005 to 0.5 percent by weight, based on the liquid diene polymer The gelation inhibitor can be used as such or in the form of a solution in an organic

Solvents are used.

The addition reaction of maleic anhydride to the liquid diene polymer is usually in In the absence of a solvent, it can also be carried out in the presence of an organic solution medium. Examples of usable Solvents are aliphatic hydrocarbons such as liquid paraffin, n-paraffins and petroleum ether, alicyclic hydrocarbons, such as cyclohexane and isopropylcyclohexane, aromatic hydrocarbons, such as benzene, toluene, xylene and durol, and esters, such as

Ethyl acetate or butyl acetate. Furthermore, ketones,

like acetone or methyl ethyl ketone, and dioxane, be used.

The air-drying properties of the invention

Maleic anhydride adducts produced by jbo made can be accelerated considerably by adding conventional drying agents such as cobalt naphthenate. The paints Polyols, polymercaptans, polyamines or polyphenols

b5 can be added.

The examples explain the cr-finding. Parts and Percentages relate to weight, unless otherwise stated.

example 1

In a 300 ml flask, make a

certain amount of an oiling inhibitor listed below in Table I and 160 g of one

liquid polybutadiene presented with the following properties:

Viscosity, cP, 20 ⁰ C 660

rf ?, g / ml 0.904

Iodine number, grams of iodine per 100 g 450
Molecular weight, determined
by vapor pressure osmometry 1730
Micro structure,%,

ice-1.4 75

trans-1,4 23

Vinyl 2

After the air in the flask has been displaced by nitrogen, the mixture is ^{heated to 150 °} C. for 1 hour and stirred. 34 g of maleic anhydride are then added and the mixture is ^{heated to 190 °} C. for 5 hours. Samples are taken 3, 4 and 5 hours after the start of the reaction and examined for maleic anhydride conversion by gas chromatography. When the reaction has ended, the maleinized polybutadiene is dissolved in xylene to a solids content of 70% and the viscosity is determined at 25 ° C. using a Ε-type viscometer. The results and the results of comparative experiments are summarized in Table 1. It can be seen from the table that the gelling inhibitors used according to the invention, when used in the same amount as copper naphthenate, develop a greater effect and do not noticeably impair the conversion of maleic anhydride.

Table I.

attempt

Gelation inhibitor

Lot.

% Viscosity by weight
in solution,
cP, 25 (

Maleic anhydride conversion,
%, after hours

3 hours.

4h

5h

1 2-mercaptobenzothiazole 0.0300 820 98.8

2 2-mercaptobenzimidazole 0.0300 960 98.7

3 2-mercaptoimidazole 0.0300 930 98.9

4 2-Hydroxy-4-methylthiazole 0.0300 1530 98.6 Comparison 1 no additive - 4004 98.8 Comparison 2 copper naphthenate 0.0300 2960 98.7

99.1 99.9 99.2 99.9 99.1 99.9 99.2 99.9 99.1 99.9 99.1 99.9

Example 2

166 g of the liquid polybutadiene used in Example 1 are placed in a 300 ml flask and the gelation inhibitor listed in Table II is added. The air in the flask is then displaced by nitrogen and the mixture is ^{heated to 100 °} C. for 1 hour. Then 34 g

Table Il

Entered maleic anhydride, and the reaction is carried out ^{at 190 0 C for 5 hours.} When the reaction has ended, the maleinized polybutadiene is dissolved in xylene to a solids content of 75% and the viscosity is determined at 25 ° C. The results are summarized in Table II. The table shows the 4 (i excellent action of the gelation inhibitors used according to the invention.

attempt

Gelation inhibitor

Lot,
TPM,
based
polymer viscosity
in solution,
to cP, 25 ( Maleic acid
anhydride-
Sales, % 100 750 99.9 100 830 99.9 200 660 99.9 100 600 99.9 - 6800 99.9 300 2600 99.9

1 N-tert-butylbenzthiazylsulfenamide

2 N-Cyclohexylbenzthiazylsulfenamide

3 N-Hydroxydiethylenbenzthiazylsulfenamäd

4 Zinc salt of 2-mercaptobenzothiazole comparison 1 no additive

Comparison 2 copper naphthenate

Example 3

In a 300 ml flask equipped with a stirrer, 83 g of the polybutadiene used in Example 1 and 83 g of a liquid 1,2-type polybutadiene having a number average molecular weight of 1000 and a microstructure of 92% vinyl groups and 8% trans-1,4 structure. After displacing the air in the flask with nitrogen, the mixture is heated. After reaching a temperature of 100 ° C 28 g of maleic anhydride and the gelation inhibitor zugesetzL shown in Table III The reaction is carried out for 5 hours at 190 ⁰ C. The maleic anhydride conversion is determined quantitatively by gas chromatography. The viscosity of the maleinized product is determined on a xylene solution with a solids content of b5 75%. The results are summarized in Table III. The table shows the excellent action of the gelation inhibitors used according to the invention.

ίο

Table ill

attempt Gelation inhibitor Lot, Viscosity in solution, eP, 25 ( Maleic acid T. p. M., anhydride- based Sales, % on polymer 1 Zinc salt of 2-mercaptobenz- 100 2300 99.9 thiazole 2 N-Cyclohxylbenzthia / yl- 100 1280 99.9 sulfenamide

Comparison 1 no addition

Reaction mixture gels after 2 hours. at 190 C; Reaction aborted

Claims (1)

Claim: Process for the production of adducts from maleic anhydride to liquid diene polymers with a content of 2 to 70 percent by weight of attached maleic anhydride by reacting a liquid potybutadiene or polyisoprene or a liquid copolymer of butadiene or isoprene and at least one diolefin, olefin or an aromatic vinyl compound with a molecular weight from 150 to 5000 and a viscosity of 2 to 50,000 ocP at 30 ⁰ C with maleic anhydride in the presence of 0.001 to 5 percent by weight, based on the liquid diene polymer, of at least one gelation inhibitor at temperatures of 120 to 230 ⁰ C for 1 to 10 hours , characterized in that the gelation inhibitor is at least